The present invention relates to a printer which interlockes with its host computer to output various data on-line or to be employed as a data-processing terminal equipment for printing out the data off-line according to its operation conducted by an operator.
Consequently, in printing operation of this type of the printer, it is preferable to employ and select printing media, i.e., continuous-forms such as journal paper and the like, and cut-forms such as letter-size or legal-size paper of predetermined width, in accordance with a user's need.
In this case, it is necessary to provide a forms-feed unit for enabling the user to employ various kinds of forms in the printer. However, it is difficult to handle at a time such various kinds of forms such as the continuous-forms together with the cut-forms in a single feed unit. Consequently, in the printer, it is necessary to mount at a time a plurality of the forms-feed units corresponding to the various kinds of forms on a printer main body of the printer, or it is necessary to enabling the printer main body to be selectively coupled with such plurality of the forms-feed units.
In the former case, generally, at least two kinds of the forms-feed units one of which is a continuous-forms feed unit and the other of which is a cut-forms feed unit are integrally incorporated in the printer main body.
However, there is a case that the user needs only one kind of the forms-feed unit, which leads to a disadvantage that the user must purchase a needless forms-feed unit incorporated in the printer together with his needing forms-feed unit. On the other hand, on the maker's side, there is a problem in that the maker can not provide a product or printer for satisfying the user's need.
However, in order to satisfy the user's need, if various kinds of the printers each of which is provided with a specialized forms-feed unit are manufactured and provided, specifications of such products considerably increases to decrease a merit of mass production, i.e., to lead to an increase of the cost of production which is disadvantageous.
In the latter case, i.e., in the printer in which various kinds of the forms-feed units are changeably mounted on the printer main body, for example, there has been proposed that a mutual mount is provided in the same portion of the printer main body, on which mutual mount the various kinds of the forms-feed units each of which has a unit-construction can be mounted as required. Such proposal is advantageous in that, since the printer main body is mutually employed, the cost for production is decreased while the user's need to employ one kind of the forms-feed unit in the printer is satisfied. However, in case that the user needs to employ the continuous-forms and the cut-forms selectively, it is necessary to change the forms-feed units according to the needed form or paper at each time when different form is employed in the printer. Such changing operation of the forms-feed units is cumbersome and leads to a problem that the printer is deteriorated in its operability and reliability due to the possibility of the user's mistake in mounting operation of the forms-feed units, which mistake leads to a failure in the forms-feed operation.
In general, in the printer, in order to insert a front end of the continuous-form into the printer, or in order to manually insert the cut-forms one by one into the printer, it is necessary to place the printer off-line, i.e., to shut the communication between the printer and its host computer so as to enable the user to drive a forms-driving unit through his operation of switches provided in an operator panel of the printer. In case that the cut-forms are employed in the printer, various forms-feed modes are required, for example such as an automatic-feed mode and a manual-feed mode in which the cut-forms are manually inserted into the printer one by one by the operator.